Internal combustion engine



Dec. 27, 1932. u. A. H. BARKEIJ INTERNAL` COMBUSTION ENGINE Filed April 27, 1928 2 Sheets-Sheet Dec. 27, 1932. K J. A. H. BARKEIJ INTERNAL COMBUSTION ENGINE Filed April 27, 1928 l 2 Sheets-Sheet NNN@ 5c 5a i invul to@ Patented Dec. 27, 1932 UNITED STATES PATENT OFFICE `TEAN A. H. BARRETT, or Los ANGELES, cALIia'oaiuA. 'AssTGNon To GEORGE c. AEvEDsoN, or NEW Yonx, N. Y.

INTERNAL cMBUsTI'oN ENGINE Application led April 27, 1928. Serial No. 278.302.

ing the following five elements in space re- '5 Ilation towards each other as shown in thefollowing Figures 1-6. These parts are:

1. A cylinder of about 3 inches bore, 2. inlet and exhaust valve of about 'half of said diameter, 3. a restricted passage between said 13 cylinderbore and the space swept by the piston, 4. a sparkplugor plugs in said chamber where the valves are located, 5. a piston rel c-iprocating in said cylinderbore.

' The Figs. 1 and 2 show the main charac- -13 teristics of the Fi 36 and Figs. 31, 32, 34 of my application o December 4,1926, Ser. No. 152,708. The size of the throat shown in yFigs- 31 and 32,34 is approximatelyapplied in the present Fig. 2 of this application with 53 the arrangement of the cylinders in a straight line as shown in said Figure 34.- The following Figures 3, 4 are a modified arrangement of the Figs. 1, 2, the angle of the inverted inletvalve approaches the perpendicular position, the throat is further alittle-wider. The next Figures 5, 6 apply the main characteristics of the first four ligures on a diierent arrangement 'of the valves in a so called F-head, retaining thereby the main principles set forth in my application 152,708 on pages 4, in relation to the Figures 35,36.

The main principles set forth in said application are the relation in space of said 5 elements, in view ofthe following conceptions: 1. turbulence, 2. volumetric eiliciency,

3. piston slap, 4. detonation. This specific relationlwas entirely new inthe art at the time of my application No. 152,708.

These characteristics and. conceptions will a be explained more accurately in the following description without deviating from the main principles involved.

This inventionE relates specially to the comp `loustion chamber of internal combustion en- J gines of the mixture type operating on a four stroke cycle, and more especiallyrelates to four most important problems and concepv tions which are mentally widely a art, but

r physically and mechanically v'y c osely re- 3 lated. These conceptions are: 1. turbulence and volumetric eiiciency, 2. piston slap, 3. detonation.

It has been well known in the art, almost from the beginning, that agitation and turbulence lin a volume of pure air and also in a '55 mixture charge will increase the flame propagation and combustion appreciably. In the lattertype of engine using a mixture this acceleration, however,l produces sometimes detonation, depending upon the amount of turbulence. If the turbulence is too great, detonation will appear quicker, than when said turbulence is less, a v ery important phenomenon in this invention which can only be avoided by employing very exact relations between certain parts of the engine.

This turbulence is produced in the mixture type of engine in two Ways 1. By a restricted passage between the cylinderbore and the explosion space,"where the valves andthe sparkplug. arelocated, 2. By the squeezing effect caused by the cooperation and near approach of the piston top and the undersurface of the cylinderhead. -This latter turbulence may be produced in the present invention in a way dierent from that widely used in the art. l

If said passage is narrow, the turbulence produced by -said passage is violent during the entire compression period, but the volu- .S0

' metric 'eiiicien'cy will be small, especially at high speeds, as the valves are located beyond said restricted passage considered from the cylinderbore. Y

If this passage is wide, the turbulence willl "85 be very little but the Ivolumetric eiiciency very high, given of course, valves of suiicient size, approximately half the cylinder-bore or even larger thanthat. p f

In the. present arrangement a compromise go has been found between factors aili'ecting the volumetric eilciency, which will produce on one hand suiicient turbulence and on the other hand suicient capacity to fill the cylinder at high speeds beyond 2000 revolutions '195 a minute, up to 7000 R. P. M. The restricted passage 'has to be substantially greater than the effective inlet valvearea (that is' the efficiency of a certain valve without this restricted passage). The inlet valve has usw-'S10o ally a diameter half of the cylinderbore, so that its area is about vr compared with the area of 4-1r of the'cylinder. The restricted passage, 5 (see Fig. 7), can therefore be made much larger than the inlet valve but smaller than the cylinderbore, in order to maintain the highest possible volumetric eliiciency and more or less turbulence, required for certain high speeds and absence of detonation, due

104 solely or greatly to this cause of turbulence.

In view of the second cause of turbulence a similar compromise between degree of turbulence and volumetric efliciency can be effected Without disturbing the first proportion,

.15 which can be effected in the explained relation and sizes.

Said turbulence, as said, can further be ef fected b the cooperation of the piston and cylinder ead by squeezing the gases therebe# 20. tween in the combustion chamber during the last part of the up-stroke of the piston. This squeezing effect is far more important for turbulence and detonation than said rst' agent and has no influence whatsoever on the volumetric efficiency of the engine, but has a marked influence" on the two other problems mentioned, piston slap and detonation. If the piston approaches said head very yclose and with great area, within l of an inch, the

turbulence, as said, will be still very great,

but the piston slap will be very much pronounced on account of the too sudden sidepressure (unbalanced pressure) on the pis-v ton. The turbulence in that case will be too great at certain speeds and detonation will be very marked witlicertain. compression ratios, especially if a motor accumulates in said spacel carbon after some usage.

If said piston approaches said head at a distance of more than fof an in ch'for a three inch bore (the drawings Figs. 1-4 show just about 31, for a S-inch bore, and Figs. 5 and 6` show about the maximum of 2/16 inch for a bore of 2 inches as shown in Fi 3, 4. In

.45 Figs. 5 and 6 this bore of Figs. 3 and 4 has been decreased to accommodate said Figures 5 and 6 on the same level for comparison bertween the two types, incorporating the same said principles) and less than 3/16 aboutof 5 an inch, the turbulence will gradually de-- crease but the piston slap will appear suddenly and will not be more pronounced than in an en 'ne having a standard combustion head wit out any restriction between explosion space and space swept by the piston.'

a mechanical minimum, the turbulence required 1s present 1n a suiiiclent degree to eliminate instead of cause detonation at said pressure, and to allow compressions of 5.5 and I such) is due mainly to three factors-a. to

the eifectof the throat at the place where the valves are located, b, to the second throat which is placed between the explosion space in the head and the expansion space in the cylinder (or the additional explosion space as proposed here also in Figs. 5, 6), c., to the three curves in the passage traversed from the inlet manifold to the cylinder, and in reverse direction from the cylinderspace to the exhaust manifold, if the .inlet valve and exhaust valve are placed upright in the c linder beside the cylinder. This second pro lem is solved by considering the close mechanical relationship of these three factors. The first factor is merely a matter of degree, the size of the inlet and exhaust valve, but the two other factors incorporate the invention of placing said first two elements in such a relation that the third factor is eliminated prac tically to a very great extent, by placing the inlet valve, or both the inlet and exhaust valve, above the second throat in close proximity to said throat. This relationship can of course be effected in two ways, one in which both valves are included as proposed in said application 152,708 the other in which only v one valve (and, of course, the inlet valve in a greater degree than the exhaust valve, as itv is very easy to get rid of the gases, but diliicult to gety them in the cylinder without a compressor) is involved.

As already said in connection with the first problem turbulence, the piston slap can -be eliminated according to the present invention, by forming an additional Vexplosion space located in the cylinder or in the head, t pressure will be exerted from the outset upon the entire surface of the piston. It would be more diiiicult to apply this feature f. i. in the form shown in Figs. 5, 6 in the cylinder, to

an engine of the L-head type, because the cubical contents of the combustion chamber can be varied only within very narrow limits, and the space in the cylinderhead is, in conse uence of the placing of both the valves uprig t beside the cylinder already at about the maximum that is permissible. If, however, one or both valves be placed in the head, the compression volume Arequired for the bore,

e effect thereof being'that the explosion stroke and degree of compression, can be made small enough to admit of an additional explosion space in the cylinder, as hereinafter described. This does not mean, however, that this could not be applied on an L-head motor. l

The third problem (detonation) which is common to nearly all'engines, is partially solved by means of the construction hereinafter described. -My theory in this regard is that, if the gaseous mixture in the head or in the cylinder be ignited or preignited, the pressure thus suddenly generated in one of these spaces cannot be propagated quickly enough in the other because of the intermediate contraction or throat. It cannot, of course, be asserted positively that this theory is correct, since the nature of detonation is still a mystery. But the phenomenon is that detonation ris a superaccelerated flame propagation, andthe throat will always have a tendency to impede this superacceleration, be this a cooling phenomenon of the yet unburned part of the gas after initial ignition, or any other 'phenomenon (thermo dyn).

/In View of the patent to E. F. Roberts No. 1,138,892 and the Patent 1,545,930 t0 J. G. Vincent, and the Patent 1,698,078 to the same J. G.' Vincent, it is of extreme importance to explain more explicitly the importance of the additional chamber .5a between the top 3 of the piston in top position and the undersurface 4 of the head. If the piston appro-aches the head as close as ismechanically allowable about 1/32 of an inch or even less, (as proposed in Patent 1,474,003 to H. R. Ricardo), this thin space 'is not, or only partially, sufiicient to allow the pressure of the explosion on the entire piston head (independent of the'posit'ion'of the piston pin, `as proposed in said patents to Roberts and Vincent). `When ignition starts a little before the piston reaches its top position, the peak of the pressure will occur about when said piston is in top position. Therefore whatever may be the ignition point, there will be a moment that the pressure in the standard Ricardo-head (be it an L-head as proposed in said patent, or a valve-in head as proposed in this application to improve the volumet-V ric eiiciency, but both having a restricted A passage between' combustion chamber and piston-chamber, how much that may be bebore) will be at one side of the piston, causing it to tip, and will cause the too well known pinking or knocking1 sound', one of the most annoying, persistent and baiiing difficulties encountered in the construction of a practical, yet eflicient (thermal) motor. I still maintain, as I have already explained in my Patent No. 1,666,160, page 4, lines 100-105, (filed March 26, 1925) that the mechanical -explanationand solution, given doubtless in some manner related to the facttween about 85,-25/ ofthe total cylinder-- there are correct in view of the following practical facts.

A few years. after said application, about two, various engineers claim and still claim that the pinking noise is either due to the pressurebetween the top ofthe piston and the undersurface of the head, as explained in extenso in said Patent 1.698.078, or is entirely due to the pure thermodynamical aspect of the sudden combustion, or rather explosion or detonation of an unburned part of the charge. They reason that, as the charge progressively burns, that the burning gas compresses the remaining unburnt gas ahead of the iiame. The temperature and the pressure of this last unburned portion increases to about 1440o Fahrenheit absolute, so that the remaining unburned portion burns at an extreme high speed, causing instantaneoeus combustion or explosion, more properly called detonation, as happens in gunpowder and dynamite. Therefore they strive to cool this last unburned portion to prevent it from reaching that temperature, necessary for detonation. To cool it, they also construct a thin codling space between the undersurface of 'the head and the piston in top position. This thin space off more than 1/32 of an inch between about 1/ 16 to 3/16 of an inch, may be applied on any sleeve valve engine (seemy Patent 1,666,160, and divisional application No. 248,154) or on an L-head engine, see Patent 1,749,327 to W. B. Earnshaw et al., or in a valve-in-head motor, see Patent No. 1,757 ,399 to A. Taub; and also shown by applicant for an L- head and valve-in-head motor in the-Fig- ,ures 35 and 36 respectively o f his application No. 152,708 of Dec. 4, 1926, and in his a plication'No. 253,594 of Febr. 11, 1928 now Patent 1,741,355) and divisional application No. 416,865 of Dec. 27, 1929. A thin sp'ac'e` of such dimensions leaves enough, space between head and piston, even if considerable carbon has accumulated on said approaching surfaces, to prevent thepiston from tipping in the cylinder when in top position, as the Whole surface of the piston will be exposed to the pressure, when about at its maximumA (and when the piston gradually moves from one side of the cylinder Wall tosthe other sidev thereof, as explained in extenso in said Patent 1,698,078.) I believe, however, that the pressure on said entire piston surface is the deciding factor to prevent piston slap and pinking, while in said patent the pressure between the approaching surfaces is considered los all important, together with an offset position of the piston pin. This applicant believes therefore, that the height between the said two approaching surfaces is more important than the piston-pin position. The said distance of about 1/ 16 to 3/ 16 of an inch will retain at the same time the squeezing effect between head and piston, which must be retained for turbulence, in addition to the turbulence due to the restriction between combustion chamber and piston chamber, as already explained. The following facts finally prove that the mechanical explanation and solution is correct, or rather more correct tha-n any other explanation. When such clearance of more than a minimum, is applied on a sleeve valveengine, the tendency to detonation is as great as when only the minimum clearance is applied. In the latter case the pressure of the explosion is, on account of the central pressure position of the combustion chamber, exerted on said piston exactly in the same way as in said former case. In other words the. cooling effect on the last unburned portion insaid clearance space between reentrant head and piston must be very small and negligible, and is not suflicient in itself to raise the compression appreciably for higher thermal etiiciency. On the other hand, the same increase in the clearance space between head and piston, in an L-head, F-head, or valve-in-head mot-or, has an appreciable ef-y feet, so that compression can be raised appreciably to better fuel-consumption. These facts prove clearly that the cooling theory has more theoretical than practical value. It cannot have both values, as the gas is compressed against the top ofthe piston, which is very hot even in the neighborhood of the cylinder walls, so that the gases `cannot receive any cooling effect. The clearance vspace may Work more as a cushion than as al place of refrigeration. These same advantage can be obtained from said clearance space, extending over the entire piston surface, or rather for so far it approaches the head, in high speed Diesel engines, in which the combustion is during part of the time, due to the same compression action of the burned part on the un burned part .of the air and fuel mixed with said air, so fast that it resembles closely` explosion and also detonation, which is an accelerated explosion.

As said,'the height ofthe space between the undersurface of the head and said piston in top position, may be greater than that what is more than a mechanical minimum, that is il/l of an inch. The greater this height becomes the less is the squeezing effect between said head and piston and the smaller amount of gas is transferred from the cylinder space into the chamber 6a in the head, see Figure 5, and the less is the mechanical turbulence set up in said chamber 6a by the gas passing through throatv 5. YOn tne other hand, this volume of gas in compressed state between head and piston increases in ratio compared with the total volume of compression if this height is increased above 1/16 of an inch, and this is of. importance in view of the thermodynamical turbulence caused by the ignition in said first chamber 6a, which causes burned gas to compressfgases in said second chamber, which are yet' unburned,

and causes therein a` thermodynamical turbulent state, which is not caused mechanically by the ascending piston like in the combustionspace 6a, but thermodynamically by the burning of the gases in the chamber 6a, the throat between these two spaces retarding the propagation of the flame. Considering different strokes and hores, we Will presently see, that if the bore or the stroke is increased, that the volume in said second space may be increased proportionally.

With a 2 inch bore and stroke, the total displacement of the iston is about 121/2 inchs. lIf the height o said chamber is only 1/16 of an inch, the volume of the additionall chamber 5a is only about 0, 4 inch 3, or about 3/ of the total charge, and about 15o/o of the total compression volume. lIf the height is increased to 3/ 16 the volume of the second chamber is about 45 o/O thereof, 55/o remaining for the chamber in the head. With a three inch bore and stroke, the total volume of displacement is about 28 cubic inches'. The height being only 1/16, and the compression 5 atmosphere, the ratio of the volume. of the second chamber between head and piston is about 2, l of the total displacement, and about 10, 5 of the total compression space. If the height thereof` isincreased to 3/16 of an inch, these figures become approximately 6, 3 and 31, 5

If a fourth inch bore and stroke are applied, the total displacement is about cubic inches. The height of the second chamber being only 1/ 16 of an inch, the volume thereof is only l, 6 c/" of the total volume, or only 8 c/" of the total compression volume, applying again about 5 atmosphere pressure for convenience. If this `height is increased to 3/16 inch these iguresbecome respectively 4, 8 o/CJ and 24 These igures are merely rough approximations.

Vire see therefore, that the greater the stroke, or thegreater the bore plus stroke, the smaller the volume of the second chamber becomes in view of the total displacement, or the total compression volume. Reversely the smaller the bore and stroke, the greater this volume is compared with the two said other volumes. Equally, if the compression is increased above 5 atmosphere, the greater the volume of the second chamber .is to the said total compression volume; and the smaller it is, if the compression is decreased. Therefore the height of this additional chamber if more than 2/32 or 3/32 inch is not so much of importance for the equal pres sure on the entire piston surface than for the thermal eiiciency of a motor. The mechanical turbulence set up in chamber 6a may decrease in importance, and this may somewhat decrease the thermal efficiency of the combustion, but the increase of the rate of thermal eiiiciency caused by the thermodynamical turbulence set up in chamber 5a, more than compensates said eventual loss. The limits of 1/16 to 3/16 inch given, are therefore of comparative less importance for the mechanical turbulence in space 6a, than for the thermodynamical turbulence in chamber 5a. If a great bore and stroke is used, the height may be increased above 3/ 16 of an inch, to increase the volume inthe second chamber. The greater `this volume is, the more eicient the total combustion will be. The volume, lof course, of the first cham-ber has always to be considered, especially in an L-head construction, as shown in my Patent-1,7 41,255, Figs. 1, 2. In this latter construction the volume of the' chamber in the head has to be considerable, as the flow of the gas from the inlet valve has to pass this chamber in a double curve, as explained, therefore it cannot be too shallow. On the other hand if the valves, at least one, as shown in Fig. 5 of said patent, and Figs. 5, 6 of this application, is applied, in inverted position over the cylinderbore, the volume of the first chamber can be decreased, and that of the second chamber correspondingly increased. Equally, if both valves are above the'cylinderbore, as shown in Figs. 3, 4 of said application 253,594 and the Figures 174 of this application, the vol Eme can equally decreased for the first cham- As the compression can be increased way above 5 atmosphere, by means of vantiknock compounds, thegiven heights of 1/16 of an inch and 3/16 are relative, and refer to about a bore of 3 inches and a compression of about 5 to 6 atmosphere. For greater bores and strokes, greater heights may be applied (aero engines) unless the compression is raised abnormally, in which case 3/16 of an inch may give very good results for both purposes, 1 the pressure on the entire piston head 2 raising of the thermal efficiency of the total charge by causing a thermodynamic turbulence in another substantial portion of the charge 'by means of an intermediate throat.'

Other objects, as, f. i., the angle of the inlet valve above the second`throa t and in the iirst throat, of the present inventionwill 'appear in the course of the following description of the preferred forms of embodimentthereof,

reference being had to the accompanying drawings, in which- 4 Fig. 1 is a. vertical section showing part of a cylinder and cylinder head constructed in accordance with my invention;

Fig. 2 is a. diagram showing how the valves can be located by preference at an angle in the combustion chamber in each of the cylinders of a six-cylinder engine; in which the cylinders are 'arranged in a straight line instead of staggered as shown in Fig. 1.

1t is understood, however, that the valves may be placed inverted in the head in a true perpendicular position in a staggered or straight arrangement.

Figs. 3 and 4 are detail views in vertical and cross sectionrespectively; both valves being in the head at a smaller angle to the cylinder axis as in Fig. 1;

Figs. 5 and 6 are similar detail views of a modified construction, in which one of the valves is in the head and the other in the cylinder. The inlet valve is at a still smaller angle to the cylinder axis than shown in Figs. 3, 4- l In all the figures, 1 is the cylinder; 2 is the piston; 2a the space swept by the piston; 3 is the upper surface of the iston, whichhas a portion 3a which is curvedp slightly upward for a purpose stated below; 4 is a planar part of the bottom of the cylinder head 10, 4a

shows that the wall of the explosion chamber comes down to about the cepter of the cyli-nderbore in the arrangement of Figs. 3 and 4, and also in the arrangement of Figs. 5, 6. The endsv of this wall cross the'cylinderbore at 4b. It is understood, however, that the explosion chamber'may extend over the center thereof, provided, there is a restriction of a turbulence Creatin value; 5 is the restricted passage or throat etween the cylinder space 2a swept by the piston and the combustion space 6 and 6a in the head; the part 6 being that which overlies the cylinder bore, and 6a being that into which the valves 7, 7a open; 7 is the inverted inlet valve A7a is the exhaust valve, which is inverted and opens downward.

Vscrew-thread engagement.; 16 and 16a is the cup shaped body in which the valve stem 7 slides, the plungers 15 and 18 are slidingly connected with the valve stem 7; 17 is the outer spiral spring, bearing upon plunger 15;

19 is the inner spiral spring, of smallerdiameter than spring 17, and which bea-rs upon the inner plunger 19; and 20 is part of the cover.

Fig. 1 shows on an enlarged scale the construction Killustrated in Fi 36 of my said application, Serial No. 152, 08, filed December 4, 1926, except with respect to the parts 15, 16, 17 and 18, which form no part o this present invention. l

According to the construction shown in this figure, the exhaust valve 7 a is also in the cylinder head, in inverted position, but is not seen in the figure because it is directly in the rear of the inlet valve 7 (see Fig. 2). Fig. 1 shows in dotted lines the inlet valve 7 and other parts of the adjacent cylinder of the series, the stem of the valve of that cylinder being inclined in a direction oppositeto the inclination of the stem of thel valve shown in full lines.

The cylinder shown in Figs. 3 and 4 is the 5 complementary member of that shown in full lines in Fig. 1, the valve stem therein being inclined oppositely to that shown in full lines in Fig. 1. The inclination of the valve stem is believed to have advantages, but it is not 1o essential, in order to obtain the advantage of the position of the inlet (and exhaust valve if desired) valve'above the throat eliminating thereby two curves which have to be followed by the gases into the cylinder, if said Valves were placed beside the cylinder, as in standard construction.x The inclination of the valve is therefore essential to enhance further the easy flow of gases into and from the cylinder in general for said inverted position of the valve or valves above and near said throat.

What is regarded as of prime importance for the accomplishment of the objects of this invention is the location of at least one of the valves, and by preference the inlet valve, in an inverted position in the cylinder head; and good results are already obtained when the 'valve is so located above the cylinder bore that it partly overlaps the same, as shown,-

thou h this is, of course, not essential, they may e located over the center. The diameter of the valves are usually about half the diameter of the cylinderbore. In Figs. 5, 6 the diameter of the inlet valve is shown substantially greaterthan that of the exhaust valve. Though this is well known in the art, it is here of special importance as the diameter of the inlet valve is in roportion to the throat, so that the latter is a out at least 25% greater than the area of the former. Consequently, the throat has an area in greater excess of the area of the exhaust valve which circumstance insures the maximum V. E. for the exhaust valve, which is in a less favorable position than the inlet valve in view of the three curves which the exhaust gasses have to make in the arrangement of Figs. 5, 6. In the arrangement, however, of Figs. 3, 4 the inlet valve and exhaust valve are 1n the same relative position to the throat and the V. E. of both will be equivalent.

The location of the inlet valve in inverted position above the cylinder bore in an engine y having a throat between the combustion 55 space 6 and the cylinder space swept by the piston 3, accomplishes results of great practical importance. It eliminates the curves in the passage traversed by-the gasses on their way from the inlet manifold to the cylinder, i0 as in the L-head type of engine, referred to above. For the introduction of the throat between the combustion space and the cylinder introduces conditions materially different from those existing in engines of standard type. This results mainly from the fact that the combustion space, has on one side the throat or restriction where .the valves are located and on the other side a throat between it andthe cylinder, which second throat has the function of producing partially the advantageous phenomenon called turbuf lence. The greatest amount of turbulence is produced, however, by the squeezing eiiect between piston and head, and I found that a minimum clearance could easily'produce too much turbulence if said area between piston and undersurface of head is large, not if it is small. It is, therefore, better to provide a clearance between 1/32 and 3/16 0f an inch to produce a tempered turbulence, which will allow higher compression, in any of the arrangements .shown. This combustion chamber' between two throats in the gas inlet passage glves room for the gases to spread out after passing the inlet valve in an L-head motor, so that the second throat presents a considerable obstacle or check to the vmovement of the gases. This objection is completelyovercome, and without sacrifice of the desired turbulence, by locating the inlet valve 7 in an inverted position in the cylinder head; and a substantial gain in volumetric eiiiciency is the result; but only if the throat 5 as said, has a cross-section substantially greater than the effective inlet area, which is less than the area of the inlet valve itself.

As shown in Figs. 1 and 3 the piston 3, when atthe top of its stroke, projects a little way into the cylinder head, and may approach t-he adjacent part 4 thereof so closely as to leave only a very thin space 5a between.

In operation, when the inlet valve opens, the piston `descends and the gases sweep in a gentle curve formed by theinverted position of the valves down the passage 9 past the valve 7 into the combustion space 6, and through the throat 5 into the cylinder space 2a..' In this movement the gases encounter no sharp curve which would increase the friction thereof upon the walls of the passa e. Moreover, the proximity of the inlet va ve to the throat, and the compactness of the chamber 6 in the -specific form shown in Fig. 1, combine to prevent the gases from losing their impetus on the way to the cylinder; an therefore, the volumetric efficiency of this arrangement' is practically equal to that of the standard engine, with inverted inlet and exhaust valves, such for example as the Buick motor;l In this latter type, however, there is no throat, and therefore the gases do not possess in any degree theturbulence which is present in the engine herein described during the latter part of the com ression period. The slightly inclined position of the inlet valve enhances further the flow of the gases in the cylinder; but as already stated this construction is not essential, and equally not ica the overlapping of the bore by one or both valves, i. e. they may be moved towards the center.

When the inlet valve closes, the piston goes up, forcing the gases gradually through the throat 5 into the combustion space 6; and when the piston approaches the head during the last part of its upward travel, the gases are already under a compression of approximately\three to four atmospheres and hence the quantum of gas pressed through the throat at the-very last moment is relatively great. The spark passes across the points of the plug a little before the piston reaches its top position; and the flame of combustion receives therefore the full benefit of the turbulence caused by this great quantity of gas forced into the space 6. The combustion of the total mass of gas takes place almost instantaneously; but because of the throat the full force of this expansion is not exerted upon the piston. c

The exhaust valve opens just before the piston reaches its bottom position, and the latter in ascending expels the spent gases through the exhaust valve 7 a (Fig. 4) These gases receive, in making their exit, the benefit of the absence of curves, as do the combustible gases on their way in. It is, however, easier to expel the gases from the cyl-- inder and combustion chamber than to introduce the fresh gases: and for that reason the location and size of the inlet valve in the head is of greater importance than the like location for the exhaust valve. It is to be observed, however, that when the exhaust valve is thus located, as in the construction shown in Figs. 1-4, it will be less heated than in an L-head cylinder. because of the comparatively quick exit of the hot gases.

The spark plug 8 is preferably placed in a horizontal position in order to obtain the full benefit of the ejection through the throat 5 of the compressed gases. p

Inasmuch as the essential thing for the accomplishment of the main object ofthis invention is to have the inlet valve in inverted position above the throat. the exhaust valve may be placed in the cylinder as in an L- head construction, as shown in F igs. 5-6, thereby retaining for the inlet valve but not for the exhaust valve, the advantage of improved volumetric efiiciency and at the same time the advantage of a small combustion chamber in the head. This position of the inlet valve has further the specific advantage that the exhaust gases are swept from the throat against this valve on the way out towards the exhaust valve. of this-inlet valve will be higher than the same valve in the arrangement of Figs. 17V-4, and the fuel (heavy ends) may evaporate thereon before admittance to the cylinder. That amount which does not evaporate will fall towards the center of the cylinder instead of towards the exhaust valve. This The tempera-ture` inverted `position of the valve enhances further the E. of the engine.

In the arrangement shown in Figs. 1-4, this space 5a can be made a little smaller than in the arrangement shown in Figs. 5 and 6; but this difference is comparatively small compared with the difference in volume of combustion space in the head of the two types shown in this application, compared with the L-head engine-volume, which is not shown here for comparison, but in my Patent 1,741,355.

It is, of course, to be understood that .the greater (about a maximum 3/16 of an inch for a cylinderbore of 3 inches, as shown in Figs. '5, 6) additional explosion space 5o in the cylinder beyond the throat can also be applied in the arrangement shown in Figs. 1-4, as indicated by the dotted line. at 3c (Fig. 3). In that caseY the piston would go up about as far as the dividingA line between the cylinder and the head. In the construction shown in Figs. 5 and 6 the cycle of op eration has the same benefits of the absence of curves for the inlet valve as in the arrangement of Figs. 1-4. The longer axis of the explosion space is perpendicular to the cylinder axis in Figs. 5-6, instead of parallel as in Figs. 141. This valve is here shown somewhat greater in area than the exhaust valve, as in standard practice, but their relative relation to the cross-section of the throat is therefore entirely diiierent on account of their position and the curves to be made by the ingoing and outgoing gases.

In this construction the exhaust gases will meet more resistance on their way out than in the arrangement shown in Figs. 17-4.

The spark plug is in the same horizontal position and at the moment of explosion the compressed gases will exert a pressure on the entire piston surface, though the throats will here diminish its full force, the same as in the iirst arrangement. The smaller this throat is made, the smoother the engine will run; but the volumetric efficiency will be impaired if the area be made too small. The area best suited for each individual engine, in relation to its bore, stroke and maximum speed of rotation, must be determined by experiment.

Figs. 3-6 show that the longitudinal axis of both chambers and the axis perpendicular thereon, are both greater than the height of either chamber and that these axes in both chambers are rotated 90 with respect to the cylin erbore.

It is finally emphasized that compression means, a blower of the centrifugal type or the Roots type, may be applied, in which case the diameter of the inlet valve can be made smaller on account of the pressure. The relationship between thecross-section of the throat and the two valves will be correspondingly affected and become of great importance, as

vllZO the inlet valve may become smaller than the exhaust valve,'and the proportion between these elements and their relative position will be entirely changed. For this reason, applicant emphasizes here only that the area of the throat should be greater than that of the inlet valve if no compressor is used. The inverted valve above the restricted passage may be located entirely above the cylinderbore without overlapping this bore, rovided of course, the said restriction is su cient to affect the speed of flame propagation.

What is claimed is:

1.*In an internal combustion engine, the combination of a cylinder, a piston reciproeating therein, a cylinderhead, a combustion chamber in said head communicating with the space in said cylinder, swept by the piston, through a restricted passage formed by the undersurface of said head and said piston when in top position, an inlet and exhaust valve and igmtion means in said combustion chamber, one of said valves at least being -located near and above said restricted passage,

. in inverted position o ening downwardly in said combustion cham er, the cross-section of said restricted passage being greater than the cross-section ofsaid valve.

2. The combination of claim 1, in which said valve over said restricted passage is the inlet valve, the stem of said valve having a slant towards the axis of the cylinder.

3. The combination of claim 1, in which said valve over said throat is the inlet valve, the axis of said Valve having an angle to the axis of the cylinder, which is less than 90.

4. The combination of claim 1, in which said ignition means consist of sparkplug ignition means, said means in substantially vhorizontal position, facing said throat, and substantially closer to said exhaust valve than to said inlet valve.

5. Thecombination of `claim 1, in 'which said ignition means'consist of avsparkplug substantially closer to said exhaust valve than to said inlet valve.

6. In an internal combustion engine, a cylinder, a piston reciprocating in said cylinder, a combustion chamber in a cylnderhead adjoining and communicating restrictedly with the end of said cylinder at one side thereof, said combustion chamber representing a part of the effective combustion space when the piston is in the position of greatest compression, and the cross-sectional area of the communicationbetween said combustionA chamber and said cylinder being less than that of the cylinderbore, the clearance space, greater than a minimum, at the closed portion of the cylinder end, combustible gas inlet` and burned gas outlet passages for said first combustion chamber, valves for said passages and spark ignition means for said first combustion chamber, said valves having their stems pointing towards the vertical plane of the piston pin in said piston.

7. The combination of claim 6, in which at least one vave is located in inverted posi-y tion above said restricted passage between cyllnderbore and combustion chamber, 1n order to decrease the horizontal cross section strictedly with the cylinder space, said rel striction being substantially greater than the inlet valve passage in said combustion chamber, but smaller than the cylinderbore, an outlet valve passage in said combustion chamber, ignition means in said chamber at least one of said valves for said passages being over the cylinder and overlapping said restricted passage. v

10; The combination of claim 9, inwhich said inlet and said outlet valves overlap partially said cylinder bore, in order to increase the volumetric eiiiciency of said combustion engine and to decrease the volume of said combustion chamber in relation to its wall surface.

11. Aninternal combustion engine of the explosive type comprising a cylinder a cylinderhead closing saidcylinder, a piston reciprocating in said cylinder, a 'combustion chamberin said cylin crhead adjoining and communicating restrictedly with the end of said cylinder at one side thereof, the cross- 'sectional area of the communication between said combustion chamber and said cylinder being less than that of the cylinderbore, comico izo

bustible gas inlet and burned gas outletpas` sages for said combustion chamber, valves for Sald passages', and spark ignition means in4 said chamber, at least-one of said valves above the cylinderbore in order to decrease the ratio between the volume of said chamber and its'.

wall surface compared with the ratio of such a. chamber, when both of said valves are beside the cylinderbore, said valve extending its axis towards the vertical plane of the pist-on pin in said piston.

12. An internal lcombustion engine as proposed in claim 11 in which said valve above said cylinderbore is the inlet Valve, in order to increase in addition thereto the volumetric eiiciency of said engine. l'

13. An internal combustion engine of the explosive type, a combustion chamber in a cylinderhead communicating restrictedly with a cylinder with a reciprocating iston, said chamber representing all of the e ective combustion space, when said piston is in the position of greatest compression, an inlet valve and an exhaust valve in inverted position above said restricted communication in order to decrease the number of curves which the gas has to pass from the inlet manifold into said cylinder and from said cylinder in the exhaust manifold, both of said valves above said cylinderbore, spark ignition means in said chamber, .said valves extending their stems towardsthe vertical plane through the piston pin of said piston.

14. rlhe combination of claim 13, in which said valves are placed in the head at an angle towards the vertical plane of the piston pin in said piston.

15. rIhe combination of claim 13, in which said valves extend with their valve stems towards the axis of a single overheadcamshaft.

16; An internal combustion engine of the explosive type, a combustion chamber in a cylinderhead communicating restrictedly with a cylinder, a reciprocating piston in said cylinder, said vchamber representing the ma- `jor part of the effective combustion space,

when said piston is in the position of greatest compression, two valves in said chamber, in inverted position above said restricted passage and said cylinderbore, said passage located at one side of said bore and smaller than said bore, spark ignition means in said chamber at least one of said valves being at a slant extending its stem towards the vertical plane of the piston pin in said piston.

17. The combination of claim 16 in which said valves extend with their stem towards the vertical plane of the piston pin. in said piston. e

18, An internal combustion engine, comprising a cylinder closed at one end by a cylinderhead, a piston reciprocating therein, a combustion chamber in said cylinderhead located above said cylinder and communicating restrictedly therewith, said chamber representing the greater part of the eective combustion space when said piston is in top position the smaller part of the eiective combustion space being located between the undersurface of said head and the top of said piston in top position, two valves in said chamber, overlapping said cylinderbore and passage, said passage located and formed at one side of said cylinder, and smaller than said bore, ignition means in said chamber at least one of said valves having. its axis outside the vertical plane through the axis ofthe cylinder and through the axis of the piston pin in said piston.

19. An internal combustion engine of the explosive type, comprising a cylinder closed at one end by a cylinderhead, a piston reciprocating therein, a combustion chamber in said cylinderhead above said cylinder and communicating restrictedly therewith, said chamber representing a part of the combustion space when said piston is in top position the other part of the effective combustion 4 space being located between the undersurace of said head and the top of said piston in top position, two valves in said cylinder above said cylinderbore and said restricted passage between chamber and cylinderbore, said passage being smaller than said cylinderbore, ignition means in said vchamber first located substantially perpendicular to the axis of the cylinder the axes of both of said valves being outside the plane through the axis of said cylinder.

20. An internal combustion engine comprising acylinder, a cylinder head, a piston reciprocating in said cylinder below said head, two valves, an inlet and exhaust valve, in said head above said cylinder, a restricted communication between said cylinder and a combustion space in said head, containing said valves, said passage having an area smaller than the cylinderbore and the horizontal cross section of said combustion chamber, but largely in excess of the area of either one of said valves, sparkignition means in said head, the axes of both of 'said valves being located outside the plane of the axis of the cylinder.

21. IThe combination of claim 20, in which at least one of said valves extend their valvestem towards said cylinder-axis.

22- The combination of claim 20, in which said piston inl top position protrudes also a little in the cylinderhead containing said combustion chamber.

23. rl'he combination of claim 20, in which both valves extend their stem towards the plane through the axis of said cylinder and pif the piston pin of said piston in said cyliny24. The combination of claim 20, in which both of said valves extend their stems towards the camshaft axis, said valves operated directly from said single overhead camshaft.

25. In an internal combustion engine, the combination of a cylinder, a cylinder head closing the open end of said cylinder, a piston reciprocating in said cylinder, a combustion chamber in said head, inlet and exhaust valves in said combustion chamber and ignition means therein, a restricted passage formed by said head and cylinder, the crosssection of said passage being less than the horizontal cross section of said cylinderbore and that of said combustion chamber in said head, said piston approaching in top position the undersurface of said head so that an additional combustion chamber is formed between said head and said piston in top position below. said restricted passage, the height sure of the mixture, when ignited before said piston reaches its top position, is exerted over the entire surface of said piston, said ignition means igniting lirst the volume of gas in said combustion chamber in said head, and further propogating said flame through the entire width of said restricted passage into said second combustion chamber, this latter volume of compressed gas being further compressed 'and/"brought in a state of thermodynamical 'turbulence before said latter volume is ignited by said lirst volume.

26. The combination of claim 25, in which the volume of said second chamber between :seA

said head and iston is substantial compared with that of t e total compression volume.

27. The combination of claim 25, in which at least one of said valves is placed in inverted position in said head overlapping the cylinderbore, so that the volumeo said combustion chamber in said head may have a volume substantial compared with that of the additional chamber between said head and` said piston in top position. p

In testimony whereof I have signed this specification.

` JEAN A. H. BARKEIJ. 

